Home wireless networks or PANs (Personal Area Networks) can be wired (as is the case for USB type and Ethernet type networks or again according to the IEEE 1394 standards) but may also rely on the use of a wireless medium. The term used then is “wireless home networks” or “wireless personal area networks” (WPAN). The Bluetooth (IEEE 802.15.1), UWB, ZigBee (IEEE 802.15.4), IEEE 802.11e or IEEE 802.15.3 standards are to date among the most widely used protocols for networks of this type.
One type of access commonly used by such protocols is the time division multiple access (TDMA) mode. This second mode of access is a multiplexing mode used to transmit several signals on only one communications channel. This is time division multiplexing, the principle of which entails the subdivision of the available time into several time slots which are then allocated to the different devices of the network.
Radio transmission systems currently use a wide range of transmission frequencies, generally ranging from 2.5 GHz to 60 GHz. These frequencies are particularly well suited to data transmission at very high bit rates in a limited range, for example as means of connectivity between the different elements of a “home cinema” type communications network.
The use of transmission and reception antennas may furthermore play a crucial role in the quality of communications for wireless home networks of this kind. Indeed, to set up a satisfactory link budget, it is necessary to adapt the parameters of configuration of these antennas to each instance of setting up communications.
Such communications systems are however highly sensitive to interference and shadowing of radio communication links. In the context of a static configuration of a home network, these phenomena can be caused, for example, by the presence of objects such as furniture, plants, or by the presence of living beings. These phenomena may thus create isolation (i.e. cut the communication link) between a sender device and a receiver device. These phenomena therefore have a direct influence on the quality of communications in the network.
Generally, in a wireless communications system, for example a 5.1 type <<home cinema>> system supporting the transmission of video as well as audio between the different devices, the non-compressed video application uses 90% of the bandwidth of the system and necessitates the implementation of two devices (a source device for the transmission of the video data and a destination devicer for the video display), while the audio application uses only 10% of the bandwidth of the system and necessitates the implementation of six devices. The resources of the system are therefore monopolized up to 90% by only two of the eight devices of the system.
In this context, it would therefore appear to be particularly useful to be able to determine the possibility, for each of the six devices used by the audio application, to set up or establish a communication simultaneously with the communication set up or established between the two devices used by the video application. Thus, the bandwidth allocated to each of the six devices used by the audio application can be increased.
There are several known techniques for managing simultaneous communications in a communications system.
One known technique, presented in the patent document U.S. Pat. No. 6,967,944, proposes to simultaneously implement point-to-point type communications, each involving a sender device and a receiver device. This technique relies on the implementation of an analysis of the received signal strength indication (<<RSSI>>) for each receiver device. Thus, each receiver device checks the quality of the point-to-point communication. According to this known technique, the setting up of a point-to-point communication is therefore conditioned by the detection of a satisfactory quality of communication.
One major drawback of this known technique is that it entails a major latency time. Indeed, each receiver device must perform the analysis of an RSSI level. Thus, the greater the increase in the number of receiver devices (and hence the simultaneous communications to be set up), the longer is the latency time of implementation.
Furthermore, this known technique cannot be used to verify the level of interference from one communication to another communication. It is therefore possible to lower the quality of communication of the network.
Finally, the efficiency of this known technique is limited by the fact that the RSSI levels are comparables only if the receiver antennas have an identical antenna or implement a same set of antenna parameters. This known technique therefore proves to be ill-suited to the case of 60 GHz communications systems in which different sets of antenna parameters are implemented.